Leaf vs FFE

[Evsarethefuture]

My brother is considering purchasing an EV, and he asked me if I would recommend the FFE or the Leaf. Now, I wasn't sure what to tell him because he has a 60 mile round-way commute, and from my experience with the FFE im averaging around a 70 mile range. I'm familiar with the Leaf, but I was wondering if the Leaf's range is higher than the FFE's, because I was searching through the Leaf forum and I saw that many users are reporting ranges of 100+ miles. I know that that the Leaf's battery is a 24kWh and the FFE's battery is a 23kWh battery, so how can Leaf owners be hitting a 100 mile range if there battery is only 1kWh larger than ours? Is the Leaf's motor more energy efficient than the FFE's?

 

[michael]

The Leaf has a 24 kWh battery, of which approximately 21 kWH (Approx 87%) seems to be usable, based on various reports I"ve seen on the internet.

The FFE has a 23 kWH battery, of which approximately 18.8 kWH (approx 82%) seems to be usable (based on the Energy to Empty value returned on the OBD scanner).

So...the FFE is gentler on it's battery, doesn't use as much of the range but has less useful energy.

The problem is that the Leaf eats batteries. We here frequently worry about battery degradation, but to my knowledge none of us has actually experienced it. Leaf owner obsess about battery degradation and DO experience it. Those who have been spared this boast about the number of "bars" they still have.

In my opinion, the Leaf is a substantially poorer design, should be avoided even though it MAY be possible to squeak out a few more miles...until the battery degrades.

 

[TexaCali]

Also keep in mind that while you are experiencing ~70 mile range with your FFE, there are people who get ~100 mile range from their FFE. Terrain, use of climate control, freeways vs surface roads, all make a difference as you know. The Leaf owners who claim 100+ miles likely have driving conditions that would get them very similar mileage on the FFE. I have one friend who owns a Leaf and the battery degradation has been a very real and huge issue for him.

Battery issues aside, the Leaf has a bit more room in the rear seat and a very mushy ride. The FFE has much nicer seats and better handling. And then there is the appearance issue - some people like the looks of the Leaf, but I will never understand those people. :?

 

[Tim Jodice]

Where Does your brother Live? My wife bought a Leaf in dec last year I just bought a FFE last week, so far i would agree with what you are reading n the Internet. The leaf Does seem to get about 10-15% more Range. I ask where he lives because from what I have Read and learned from the dealer is the batteries suffer in the heat fully charged. My wife made out ok last winter, lowest milage was 55mi @ 7F in the mornning Warming up to 15-20F. So bases on what we have learned and her needs when it Gets hot here we will start charging to 80% See how that goes. I bought the Focus mainly because it is just another car and Does not scream tree hugger. I would sugest he drives both and get the one he likes.

 

[twscrap]

We here frequently worry about battery degradation, but to my knowledge none of us has actually experienced it.

My 2013 sat on dealer lots for upwards of 18 months before I took possession of it with 208 miles on the clock. There seems to be about 3% degradation of the battery due to age and/or how the battery was treated while in the dealer's possession.

That said, I still did 111 miles on a single charge last week even with that degradation.

 

[michael]

I"m not sure if you're agreeing that there are no reports of degradation (saying 3% is negligible) or disagreeing (saying that 3% is significant), but my real question is how you determined this?

As far as I know, nobody on this board knows for sure the actual usable capacity of a new FFE battery. Many people have suggested 19.5 kWH, but my own OBD reading suggest a number nearer 18.5 kWH. Let's say the range of estimate is 19 kWH +/- 3%.

What is your present measured usable capacity and how did you measure it?

 

[hybridbear]

We here frequently worry about battery degradation, but to my knowledge none of us has actually experienced it.

My 2013 sat on dealer lots for upwards of 18 months before I took possession of it with 208 miles on the clock. There seems to be about 3% degradation of the battery due to age and/or how the battery was treated while in the dealer's possession.

That said, I still did 111 miles on a single charge last week even with that degradation.

How have you measured the degradation? Have you reviewed it with the dealer?

 

[michael]

Is the Leaf's motor more energy efficient than the FFE's?

No, it's less efficient because it's smaller. There are greater resistive losses in the smaller motor at a given power level.

 

[twscrap]

I"m not sure if you're agreeing that there are no reports of degradation (saying 3% is negligible) or disagreeing (saying that 3% is significant), but my real question is how you determined this?

As far as I know, nobody on this board knows for sure the actual usable capacity of a new FFE battery. Many people have suggested 19.5 kWH, but my own OBD reading suggest a number nearer 18.5 kWH. Let's say the range of estimate is 19 kWH +/- 3%.

What is your present measured usable capacity and how did you measure it?

I find the 3% to be negligible, although it is similar to what I saw over a two year period and 20k miles in the ActiveE.

Before taking delivery on my FFE, I asked the specific question of the dealer as to what would happen if I immediately found out that 1.5 years of almost zero use had had a deleterious effect on the traction battery. Got the typical 'it's got a warranty' answer. It didn't take long driving around for me to suspect there was likely a fair bit of degradation. To be fair, that impression was based on the 19.5 kWh number that has been routinely kicked around here.

To ascertain whether I did in fact have a degradation issue, I set up an experiment to test my theory. Six full to empty runs to determine available capacity. Three highway driving and three surface street runs. All were under similar temperature and weather conditions with no climate or accessory usage other than the radio.

I'm fortunate in that I live at the bottom of a steep hill with a 1/4 mile loop at the top of the hill that allowed me to push the car to the very end with almost zero risk on my part (Risk being defined as pushing the car a maximum of 1/8 mile to get it home). Those six runs resulted in the following total consumptions:

Surface Streets: 18.1, 18.1, 18.2
Highway: 18.2, 18.0, 18.1

Based on your daughter running it to empty and your observing 18.8 kWh and that being seemingly confirmed above by the ObD scanner, degradation would seem to be somewhere between 3-4% assuming you have no degradation in your battery.

How have you measured the degradation? Have you reviewed it with the dealer?

Haven't reviewed with the dealer as there's no point until I'm near the limits of the warranty.

 

[jstack6]

MY FFE has not lost any battery capacity after more than a year in the Phoenix heat. I check it with a SCAN GAUGE made just for the FORD plugins.

That being said the Air Cond uses 2 to 3 times more energy than the LEAF. Mine drops 30 miles and my wife's LEAF only drops 2-10 on a hot day with a full charge. The Focus battery looks like it could last 20 years.

Both have very similar range. The new 2015 LEAF has Desert Heat Tolerant batteries. That would be good. I's tell them to lease any electric since they change so fast and keep dropping the price. It could be hard to sell as more choices come out.

 

[WattsUp]

The new 2015 LEAF has Desert Heat Tolerant batteries.

Haha... in the FFE, this is simply called "the battery".

 

[dmen]

MY FFE has not lost any battery capacity after more than a year in the Phoenix heat. I check it with a SCAN GAUGE made just for the FORD plugins.

At the risk of asking a dumb question, how do you know the scan gauge is accurate, specifically in its energy to empty figure? Have you driven your car full to empty, using the scan gauge to show how much energy was used, and comparing this to the energy use reported on the car's trip meter and to the reported energy to empty at the beginning of the trip? I believe I read somewhere that if you took your FFE to dealer for premature battery degradation, they would have to run the battery full to empty to determine capacity. If the OBD port can provide accurate data in this regard, why wouldn't Ford just measure with a reader?

I find twscrap's capacity-measuring runs particularly interesting and supporting the full discharge enhanced trip meter method as accurate. If the trip meter recordings were not accurately reflecting energy recaptured (which has been offered as a possible reason for those of us measuring 19.5kWh available vs 18.5 from OBD) then the measurements for city driving, where a lot more regen braking is employed, would differ from the highway driving. But they didn't differ significantly.

 

[twscrap]

I find twscrap's capacity-measuring runs particularly interesting and supporting the full discharge enhanced trip meter method as accurate. If the trip meter recordings were not accurately reflecting energy recaptured (which has been offered as a possible reason for those of us measuring 19.5kWh available vs 18.5 from OBD) then the measurements for city driving, where a lot more regen braking is employed, would differ from the highway driving. But they didn't differ significantly.

A couple of points that I should clarify - even on the highway drives, there was a fair amount of service street driving as I'm 4.5 miles off the highway - minimum was ~11 miles max was 14 for the three runs as I kept circling in my neighborhood until the car ran out. Net result is that even on the 'highway' runs, 15-20% of the miles were surface streets. While not exactly city driving, there is a fair amount of regenerative braking on the route - especially the section in my neighborhood where I kept circling past my street.

Second, I kept strictly to speed limits on the highway (not so much on the surface streets) which range from 55-65 on the route I took.

And finally, the surface street route that I took was a driving back and forth to my mother's house which is mostly 40-45 mph. And while it included some lights and stop signs, it's not exactly city driving.

 

[michael]

You are asking the same types of questions I've been thinking about.

I'm reaching some conclusions...

1. Battery capacity can only be measured accurately under some specified set of conditions, most importantly temperature and current draw. For this reason, the dealer test is the most meaningful.

The reason this is important is because the effective series resistance varies with temperature (as well as battery condition, state of charge, etc). And the energy lost into this ESR varies with discharge rate.

In other words, you would expect a different reported capacity on the dash display for a low temperature high speed dash up a mountain compared to a 30 mph level drive at a moderate temperature.

For this reason, the dash display of energy cannot be relied upon as an accurate indicator of battery capacity. The result is dependent upon the test conditions. It probably gives a good number for the amount of energy flowing out of the battery, but it is only an estimate of battery capacity.

2. Modern battery fuel gauge systems are also estimates, but good ones (I assume and hope the FFE has a good one...) attempt to dynamically model and estimate remaining based on measurements of battery voltage, temperature, charge counting, and possibly other factors. But even these are estimates. A good battery fuel gauge might even indicate an increase in ETE without charging in a parked car if the battery warms up during the day. I haven't actually seen this in the FFE, but I will see if I have an opportunity to measure early morning and late afternoon with the car unused.

However, since the battery fuel gauge (ETE value) most likely includes some estimate of the effects of varying ESR, I would trust it more than the dash display.



If anyone wants to learn more about battery fuel gauges, Texas Instruments has a series of video lectures

http://www.ti.com/lsds/ti/power-management/battery-fuel-gauge-support-community.page

 

[hybridbear]

2. Modern battery fuel gauge systems are also estimates, but good ones (I assume and hope the FFE has a good one...) attempt to dynamically model and estimate remaining based on measurements of battery voltage, temperature, charge counting, and possibly other factors. But even these are estimates. A good battery fuel gauge might even indicate an increase in ETE without charging in a parked car if the battery warms up during the day. I haven't actually seen this in the FFE, but I will see if I have an opportunity to measure early morning and late afternoon with the car unused.

However, since the battery fuel gauge (ETE value) most likely includes some estimate of the effects of varying ESR, I would trust it more than the dash display.

I think other Fords do this. I track all my trips in our Fusion Hybrid and I've found that the SOC will change while the car is off. When the HVB is warm and cools the SOC increases while the car is off. This is what you're referring to, correct?

 

[michael]

Not exactly. It's even more complicated.

There are three different battery displays that I have seen:

1. The Battery % on the dash, which reads from 100% to 0%

2. The State of Charge on the OBD scanner, which reads from approximately 89% to approximately 8%

3. The Energy to Empty on the OBD scanner, which read from approximately 18.5 kWH to 0 kWH.

Plus in addition there is the trip energy gauge on the dash.


Earlier today, for example

Battery% = 29

Battery temperature = 82 F

State of charge = 31.3%

Energy to Empty = 4.88 kWH


The car has been out in the sun, not running, not charging, and now:

Battery% = 30

Battery temperature = 84 F

State of charge = 32.4

Energy to empty = 5.15 kWh


Now, obviously the battery didn't actually gain any energy while sitting for three hours. What changed was the car's estimate of the available energy. Due to warming of the battery? Inaccuracies of the system? The battery relaxing and reaching a higher voltage? I don't know yet, but there was a 5.5% change in the car's estimate of remaining energy while sitting.

This reminds me of discussions I've seen on the Tesla boards. People there complain about the loss of energy overnight following charging. I don't think this is really happening. I think the car's displayed estimate of range is changing, possibly due to the battery cooling, the voltage relaxing after charge, or some other factor.

So I wouldn't put too much emphasis on the results of trip meter energy readings as an indicator of small amounts of battery degradation or lack of same. Unless the test conditions are exactly the same, I would differences in the results based on many factors. TWSCRAP's results are stunningly consistent with each other (good job!) but I don't have reason to believe or disbelieve that they mean his battery would perform differently than mine or anyone else's.

 

[twscrap]

Now I've got an itch to try a fourth run under different temperature conditions. Unfortunately the FFE became the SO's DD when we picked up the i3, so it may be awhile before I get to do it.

 

[hybridbear]

Not exactly. It's even more complicated.

There are three different battery displays that I have seen:

1. The Battery % on the dash, which reads from 100% to 0%

2. The State of Charge on the OBD scanner, which reads from approximately 89% to approximately 8%

3. The Energy to Empty on the OBD scanner, which read from approximately 18.5 kWH to 0 kWH.

Plus in addition there is the trip energy gauge on the dash.


Earlier today, for example

Battery% = 29

Battery temperature = 82 F

State of charge = 31.3%

Energy to Empty = 4.88 kWH


The car has been out in the sun, not running, not charging, and now:

Battery% = 30

Battery temperature = 84 F

State of charge = 32.4

Energy to empty = 5.15 kWh


Now, obviously the battery didn't actually gain any energy while sitting for three hours. What changed was the car's estimate of the available energy. Due to warming of the battery? Inaccuracies of the system? The battery relaxing and reaching a higher voltage? I don't know yet, but there was a 5.5% change in the car's estimate of remaining energy while sitting.

This reminds me of discussions I've seen on the Tesla boards. People there complain about the loss of energy overnight following charging. I don't think this is really happening. I think the car's displayed estimate of range is changing, possibly due to the battery cooling, the voltage relaxing after charge, or some other factor.

So I wouldn't put too much emphasis on the results of trip meter energy readings as an indicator of small amounts of battery degradation or lack of same. Unless the test conditions are exactly the same, I would differences in the results based on many factors. TWSCRAP's results are stunningly consistent with each other (good job!) but I don't have reason to believe or disbelieve that they mean his battery would perform differently than mine or anyone else's.

On the hybrid I cannot get Energy to Empty, that comes from a module that doesn't exist on the hybrid, just the Energi & Electric, because that PID is measured by the SOBDMC module which controls wall charging.

However, the hybrid does track 2 different SOC numbers, absolute SOC & displayed SOC. Both will change sometimes while the car is off. Other times they will not change at all even if the car sits for days. The kWh stored in the battery aren't actually changing, but the way the car is interpreting the battery SOC is.

 

[unplugged]

This reminds me of discussions I've seen on the Tesla boards. People there complain about the loss of energy overnight following charging. I don't think this is really happening. I think the car's displayed estimate of range is changing, possibly due to the battery cooling, the voltage relaxing after charge, or some other factor.

Actually, the Tesla "vampire" loss is well-documented. Tesla has managed to reduce the vampire loss in the Model S to about 1 kWh each night, but it is still unique among BEVs. See the bottom of this page two article about Model S software updates and the segment on "Sleep Mode." http://www.greencarreports.com/news/1092515_tesla-model-s-electric-car-software-updates-since-2012/page-2

 

[WattsUp]

Actually, the Tesla "vampire" loss is well-documented. Tesla has managed to reduce the vampire loss in the Model S to about 1 kWh each night

What is the 1 kWh going to? Battery temperature control? Running the computer?